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1.标量函数：结果为一个单一的值，可包含逻辑处理过程。其中不能用getdate()之类的不确定性系统函数.
<div class="codetitle"><a style="CURSOR: pointer" data="29342" class="copybut" id="copybut29342" onclick="doCopy('code29342')"> 代码如下:<div class="codebody" id="code29342">
--标量值函数
-- ================================================
-- Template generated from Template Explorer using:
-- Create Scalar Function (New Menu).SQL
--
-- Use the Specify Values for Template Parameters
-- command (Ctrl-Shift-M) to fill in the parameter
-- values below.
--
-- This block of comments will not be included in
-- the definition of the function.
-- ================================================
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author: <Author,Name>
-- Create date: <Create Date,>
-- Description: <Description,>
-- =============================================
CREATE FUNCTION <Scalar_Function_Name,sysname,FunctionName>
(
-- Add the parameters for the function here
<@Param1,@p1> <Data_Type_For_Param1,int>
)
RETURNS <Function_Data_Type,int>
AS
BEGIN
-- Declare the return variable here
DECLARE <@ResultVar,@Result> <Function_Data_Type,int> -- Add the T-SQL statements to compute the return value here
SELECT <@ResultVar,@Result> = <@Param1,@p1> -- Return the result of the function
RETURN <@ResultVar,@Result> END
2.内联表值函数:返回值为一张表,仅通过一条SQL语句实现,没有逻辑处理能力.可执行大数据量的查询. <div class="codetitle"><a style="CURSOR: pointer" data="21056" class="copybut" id="copybut21056" onclick="doCopy('code21056')"> 代码如下:<div class="codebody" id="code21056">
--内联表值函数 -- ================================================
-- Template generated from Template Explorer using:
-- Create Inline Function (New Menu).SQL
--
-- Use the Specify Values for Template Parameters
-- command (Ctrl-Shift-M) to fill in the parameter
-- values below.
--
-- This block of comments will not be included in
-- the definition of the function.
-- ================================================
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author: <Author,>
-- =============================================
CREATE FUNCTION <Inline_Function_Name,FunctionName>
(
-- Add the parameters for the function here
<@param1,int>,
<@param2,@p2> <Data_Type_For_Param2,char>
)
RETURNS TABLE
AS
RETURN
(
-- Add the SELECT statement with parameter references here
SELECT 0
)
GO
3.多语句表值函数:返回值为一张表,有逻辑处理能力,但仅能对小数据量数据有效,数据量大时,速度很慢. <div class="codetitle"><a style="CURSOR: pointer" data="99030" class="copybut" id="copybut99030" onclick="doCopy('code99030')"> 代码如下:<div class="codebody" id="code99030">
--多语句表值函数 -- ================================================
-- Template generated from Template Explorer using:
-- Create Multi-Statement Function (New Menu).SQL
--
-- Use the Specify Values for Template Parameters
-- command (Ctrl-Shift-M) to fill in the parameter
-- values below.
--
-- This block of comments will not be included in
-- the definition of the function.
-- ================================================
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author: <Author,>
-- =============================================
CREATE FUNCTION <Table_Function_Name,@p1> <data_type_for_param1,@p2> <data_type_for_param2,char>
)
RETURNS
<@Table_Variable_Name,@Table_Var> TABLE
(
-- Add the column definitions for the TABLE variable here
<Column_1,c1> <Data_Type_For_Column1,
<Column_2,c2> <Data_Type_For_Column2,int>
)
AS
BEGIN
-- Fill the table variable with the rows for your result set RETURN
END
GO
4.游标:对多条数据进行同样的操作.如同程序的for循环一样.有几种循环方向控制,一般用FETCH Next. <div class="codetitle"><a style="CURSOR: pointer" data="38550" class="copybut" id="copybut38550" onclick="doCopy('code38550')"> 代码如下:<div class="codebody" id="code38550">
--示意性SQL脚本 DECLARE @MergeDate Datetime
DECLARE @MasterId Int
DECLARE @DuplicateId Int SELECT @MergeDate = GetDate()
DECLARE merge_cursor CURSOR FAST_FORWARD FOR SELECT MasterCustomerId,DuplicateCustomerId FROM DuplicateCustomers WHERE IsMerged = 0
--定义一个游标对象[merge_cursor]
--该游标中包含的为:[SELECT MasterCustomerId,DuplicateCustomerId FROM DuplicateCustomers WHERE IsMerged = 0 ]查询的结果. OPEN merge_cursor
--打开游标
FETCH NEXT FROM merge_cursor INTO @MasterId,@DuplicateId
--取数据到临时变量
WHILE @@FETCH_STATUS = 0 --系统@@FETCH_STATUS = 0 时循环结束
--做循环处理
BEGIN
EXEC MergeDuplicateCustomers @MasterId,@DuplicateId UPDATE DuplicateCustomers
SET
IsMerged = 1,
MergeDate = @MergeDate
WHERE
MasterCustomerId = @MasterId AND
DuplicateCustomerId = @DuplicateId FETCH NEXT FROM merge_cursor INTO @MasterId,@DuplicateId
--再次取值
END CLOSE merge_cursor
--关闭游标
DEALLOCATE merge_cursor
--删除游标
[说明:游标使用必须要配对,Open--Close,最后一定要记得删除游标.] 5.事务:当一次处理中存在多个操作,要么全部操作,要么全部不操作,操作失败一个,其他的就全部要撤销,不管其他的是否执行成功,这时就需要用到事务. <div class="codetitle"><a style="CURSOR: pointer" data="19988" class="copybut" id="copybut19988" onclick="doCopy('code19988')"> 代码如下:<div class="codebody" id="code19988">
begin tran
update tableA
set columnsA=1,columnsB=2
where RecIs=1
if(@@ERROR <> 0 OR @@ROWCOUNT <> 1)
begin
rollback tran
raiserror( '此次update表tableA出错!!',16,1 )
return
end insert into tableB (columnsA,columnsB) values (1,2)
if(@@ERROR <> 0 OR @@ROWCOUNT <> 1)
begin
rollback tran
raiserror( '此次update表tableA出错!!',1 )
return
end end
commit
（编辑：李大同）
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